# PHYSICS

posted by .

A circular loop of flexible iron wire has an initial circumference of 168cm , but its circumference is decreasing at a constant rate of 15.0cm/s due to a tangential pull on the wire. The loop is in a constant uniform magnetic field of magnitude 1.00T , which is oriented perpendicular to the plane of the loop. Assume that you are facing the loop and that the magnetic field points into the loop.
Find the magnitude of the EMF induced in the loop after exactly time 9.00s has passed since the circumference of the loop started to decrease.

• PHYSICS -

L2=L1- (ΔL/Δt) •t=168-135=33 cm
EMF=-dΦ/dt =- d(B•A•cosα)/ dt.
cosα=1.
L1=2•π•R1
R1=L1/2•π=168/2•3.14=26.7 cm
A1=π•R1²=3.14•26.7²=2246 cm²=0.2246 m²

L2=2•π•R2
R2=L2/2•π=33/2•3.14=2.25 cm
A2=π•R2²=3.14•2.25²=86.7 cm²=0.0087m²
EMF=-dΦ/dt =- d(B•A•cosα)/dt.
cosα=1.
EMF=-B•ΔA/Δt=
= -1•(0.2246-0.0087)/9=0.024 V

## Respond to this Question

 First Name School Subject Your Answer

## Similar Questions

1. ### physics EM

Shrinking Loop. A circular loop of flexible iron wire has an initial circumference of 167 cm, but its circumference is decreasing at a constant rate of 10.0 cm/s due to a tangential pull on the wire. The loop is in a constant uniform …
2. ### Physics

A 2.00 cm x 2.00 cm square loop of wire with resistance 1.30×10^−2 Ohms is parallel to a long straight wire. The near edge of the loop is 1.00 cm from the wire. The current in the wire is increasing at the rate of 110 A/s. What …
3. ### Physics

Would someone check this please? A circular loop of wire of radius 0.10 m and of resistance 2.0 ~ 10−3 ƒ¶ is in a region where there is a uniform magnetic field B. The field is at 30‹ to the normal to the plane of the
4. ### Physics

Would someone check this please? A circular loop of wire of radius 0.10 m and of resistance 2.0 x 10^−3 ohms is in a region where there is a uniform magnetic field B. The field is at 30deg to the normal to the plane of the wire
5. ### Physics

Would someone check this please? A circular loop of wire of radius 0.10 m and of resistance 2.0 x 10^−3 ohms is in a region where there is a uniform magnetic field B. The field is at 30deg to the normal to the plane of the wire
6. ### physics

A long, vertical, straight wire carries a current I going upwards. The wire is perpendicular to the plane of a circular metal loop and passes through the center of the loop. The loop is allowed to fall and maintains its orientation …
7. ### Physics

Part of a single rectangular loop of wire with dimensions .35 m by .75 m (.35 is the height and .75 is the length) is situated inside a region of uniform magnetic field of 0.395 T. The total resistance of the loop is 0.690 Ω. …
8. ### physics

Two parallel wires both carry currents directed from left to right .A circular wire loop lies in the plane of the two wires, mid-way between them.As always, assume the currents are positive charges. Sketch the changes in magnetic fields …
9. ### Physics

Two parallel wires both carry currents directed from left to right .A circular wire loop lies in the plane of the two wires, mid-way between them.As always, assume the currents are positive charges. Sketch the changes in magnetic fields …
10. ### Physics

A length of copper wire is shaped into a single circular loop of circumference 63 cm, similar to that shown in the picture below. A magnetic field of strength 0.50 T is parallel to the normal of the loop. The copper wire has a resistance …

More Similar Questions